The exposed heatpipe base of the Igloo H58 heatsink measures
40x52mm in size. The 8mm diameter heatpipes are swaged in flush and machined
very flat and smooth. The four small holes in the fins (top
view) are where the wire fan clips lock into position. The plenum
behind the fan is 4mm.

Base Finish and Flatness

Flipping a heatsink over to inspect the business
end is often a simple indicator of overall cooler quality. More practically
speaking, a heatsink is in many ways only as effective as the contact it makes
with the processor - the flatter and smoother the better. Base finish is one of
the criteria that Frostytech measure in the course of evaluating heatsinks, and
it involves two distinct aspects. Surface Finish is the first; this is
calculated with the aid of Surface Roughness Comparator that has a cross section
of common machine surface finishes and their numerical surface roughness
equivalents in microinches. The second is Surface Flatness. This is tested with
an engineers straight edge or proven flat surface, in two axis.

The exposed heatpipe base of the Glacialtech Igloo H58 heatsink
is well machined and completely flat in both axis. The surface has a very
soft ridged texture from the tool bit. Most importantly, the heatpipes and aluminum
support plate are completely flush to one another. Surface roughness is at or better than
approximately 16 microinches, which is considered very good.